1.Field of the Invention
This invention relates generally to ceiling fans, and more particularly, to a blade fame forming a rigid unit for holding ceiling fan blade material.
2. Description of Related Art
Ceiling fans are well known, and typically include a plurality of blades extending from a motorized hub for rotation therewith to circulate air in a room. Ceiling fan blades are typically fabricated from wood and are attached to the hub via a standardized xe2x80x9cblade armxe2x80x9d or xe2x80x9cblade ironxe2x80x9d or xe2x80x9cflangexe2x80x9d having three or four bores extending through one end of the blade iron. The bores in the blade iron are matched with corresponding bores extending through the blades, and the blades are secured to the blade iron with bolts or screws, or other suitable attachment means. The opposite end of the blade iron is secured to the rotating part of the fan motor to rotate the blades. FIG. 1A shows a typical wood ceiling fan blade 1 having three holes 2 extending therethrough for connecting the blade 1 to a blade iron. FIG. 1B illustrates the fan blade 1 connected to a blade iron 3.
Materials other than wood may be used for fabricating ceiling fan blades. Non-rigid, light-weight blades may be constructed of fabric such as cloth or canvas, or other light-weight materials such as woven wicker or natural leaf. Due to the flexible nature of these types of light-weight blade materials, a frame is required to form the blade shape and support the blade material. Even if the blade material is capable of generally forming the blade shape, a rigid blade frame for these flexible blade materials prevents a ceiling fan blade from flexing under the load of the air velocity at a high fan speed.
Some known non-rigid blades may be attached to an xe2x80x9copenxe2x80x9d framexe2x80x94the frame is constructed from a single rod bent into the general shape of the blade, and one or both of the ends of the rod are connected to a blade iron. This type of blade construction is disclosed, for example, in U.S. Pat. No. Des. 306,643 to Taylor, III. Connecting the ends of the rod to a standard blade iron such as that shown in FIG. 1B is generally unsatisfactory, since the connection would not provide the required support of the blade. Therefore, a specially designed blade iron or flange, or other connection apparatus is required. Further, the open frame does not form a rigid structure until it is attached to the special blade iron, possibly resulting in damage to the blade prior to its attachment to the blade iron.
Other non-rigid blades use a xe2x80x9cclosedxe2x80x9d framexe2x80x94the frame member is bent into the general blade shape and the ends are connected together to form a continuous member. Woven wicker or other materials are connected to the frame member to form the fan blade. A conventional blade iron is not suited to attach a closed frame blade to the ceiling fan motor. Rather, a special attachment mechanism is used in which upper and lower members xe2x80x9csandwichxe2x80x9d the fan blade. Such a sandwich arrangement is conceptually illustrated in FIG. 2, which shows a connection apparatus 4 for a prior art fan blade. The connection apparatus 4 of FIG. 2 includes upper and lower members 5, 6 that are situated above and below the fan blade 7. Bolts or screws 8 extend through the upper and lower members 5,6 and the blade 7 to secure the blade to the apparatus 4. The type of attachment arrangement shown in FIG. 2 often does not provide a robust connection as is desired to securely connect the blades to the motor.
Thus, if a fan manufacturer offers both rigid and non-rigid, light-weight blades, multiple types of blade irons are required, which results in added costs. Additionally, if a user desires to replace typical wooden blades with wicker or natural leaf blades, for example, the existing blade irons must be discarded and special blade irons must be purchased.
The present invention addresses shortcomings associated with the prior art.
In one aspect of the invention, a fan blade frame includes a first frame member generally defining the outer periphery of a fan blade. A plate is fixedly attached to the base end of the first frame member. The plate defines a plurality of openings therethrough for connection to a conventional fan blade iron. The first frame member is fixedly attached to the plate to form a single rigid unit to provide support for blade material, even when it is not attached to a blade iron.
In certain embodiments, at least one support member is attached between the plate and the first frame member. A second frame member may further be included that has first and second ends each connected proximate to the base end of the first frame member. The support member in such an embodiment is attached to the second frame member between its first and second ends. The plate is also attached to the second frame member. The frame members may comprise steel wire, for example. The plate, frame members, and support members may be connected by welding.
In accordance with further aspects of the invention, a fan blade includes a first frame member generally defining the outer periphery of the fan blade. A second frame member has first and second ends each connected proximate to the base end of the first frame member. A plate is attached to the base end of the first frame member and the second frame member, and the plate has a plurality of openings therethrough for connection to a conventional fan blade iron. Blade material, such as woven wicker, cloth or a natural leaf is attached to the first and second frame members.